Chris B. schrieb:
> Hello,
> I need to stain polylisine - free and conjugated with peptide. Coomasie
> Brillant Blue fails with free polylysine and - for my suprise - so does
> silver.
> I'm using silver staining method from Amersham Technical Manual (as it say -
> based on Heukeshoven and Dernick 1985) but they do not describe which
> aminoacids are essential for detection.
> Any help?
> Regards,
> Chris B.
>> I used already Ag staining method described by Blum et al.
Electrophoresis 8 (1987) 93-99 for protein staining.
Also, this autor didn't describe which residues are necessary.
But there are just two possibilities how the method works:
(1) Ag+ from the fixing solution is reduced to Ag (colloid)
(2) Ag+ reacts with free -SH groups and forms an Ag-S-R complex
In the first case there must be amino acid residues present
that can be oxidized by Ag+ (cysteines and others).
In the second case there must be amino acid residues present
that can form sulfides with Ag+-salts (cysteines are the only
possibility).
Best regards,
Andreas Giessauf